13 October, 2003

Principal Investigator: Dr. Philip Kyle, New Mexico Tech, Soccoro, New Mexico

Study Site: Mt. Erebus, Ross Island, Antarctica

Project Description: Monitoring Gas Emission and Seismic Data on Mt. Erebus, Antarctica

Mt. Erebus, Antarctica, has the distinction of being the southernmost volcano, as well as one of the few continuously active volcanoes, in the world. Mt. Erebus is a stratovolcano containing a continuously convecting lava lake in its summit cone. It is this decade-scale activity of the lava lake that interests geologists.

Mt. Erebus is called a polygenetic stratovolcano, meaning that it has experienced different eruptive stages. The initial eruptive period consisted of low-viscosity basaltic lavas that created a low, broad shield cone similar to those found in the Hawaiian Islands. More viscous lavas were erupted in a later stage and form the steeply dipping (~30º) upper slopes of the volcano. The summit caldera of Mt. Erebus contains a small, steep-sided cone made up of decomposed lava bombs and anorthoclase crystals. The active lava lake is situated within this inner cone, venting gasses and occasionally erupting lava bombs and small flows. Degassing of the underlying magma system though this lava lake emits volcanic gasses into an otherwise pristine Antarctic atmosphere.

Mt. Erebus has become a model volcano for volcanological studies due to its excellent accessibility and its small strombolian eruptions. Since the early 1970's, research has been conducted primarily by scientists in the Department of Earth and Environmental Science, and the Bureau of Geology and Mineral Resources, at the New Mexico Institute of Mining and Technology. Research sponsored by the National Science Foundation has included petrography and geophysical studies of the volcano to assess the eruptive history and nature of Mt. Erebus, monitoring of the activity and degassing behavior of the lake, and analysis of the overall impact of the volcano on both Antarctica and the global environment.

The 2003-04 field season will be a continuation of research started last year. We will be installing a new integrated surveillance instrumentation (ISI) system to complement the five existing geophysical/geodetic surveillance observatories. This system will contain a broadband seismometer, dual frequency GPS receiver, tiltmeter, and a variety of environmental sensors and associated power systems. Such equipment will enable the researchers to monitor seismic activity and measure deformation of the volcano on a minute scale throughout the year. We will also be upgrading the existing ISI stations, taking GPS measurements at sites on the flanks and summit of the volcano to supplement the continuous data collected by eight existing GPS units, and collecting volcanic rock and gas samples.

Data collected through field based GPS measurements and gas sampling, in addition to the annual monitoring of the fixed seismic stations, will allow for a better understanding of the eruptive nature of Mt. Erebus as well as shed light on the general construction of volcanoes and their impact on the environment. The seismic data collected in the field and monitored year-round from the ISI stations can be inverted to create a topographic image of the magma chamber and conduits inside the volcano, helping to understand how magma and gas slugs move through volcanic systems. Measurement of the emission rates of CO2, SO2, and trace gasses and metals, on the other hand, can be used to evaluate the potential impact of volcanic activity on the East Antarctic Ice Sheet. Developing models of the internal plumbing and eruptive nature and the effects of eruptions on the environment for a volcano like Erebus goes a long way in helping scientists to better understand other volcanoes around the world. The information gained from the continued studies on Mt. Erebus is made public at the Mt. Erebus Volcanic Observatory (MEVO) website at www.ees.nmt.edu/Geop/Erebus/erebus.html.

References: Project description based on Dr. Philip Kyle's NSF grant proposal and informationi from the MEVO web site.